A majority of the court decided that the Northern Ireland Human Rights Commission, which initiated the case, did not have the standing to bring the challenge to the abortion law. The court dismissed the case without taking action.

The justices went on to say, however, that a majority finds Northern Ireland's abortion prohibitions "disproportionate" and that they violate European human rights laws.

That part of the ruling gave hope to abortion rights activists seeking to liberalize Northern Ireland's laws. Strict Northern Ireland laws that prohibit abortions in cases of pregnancy as a result of incest or rape, and in cases when the fetus has a likely fatal abnormality, have drawn scrutiny since the Republic of Ireland voted overwhelmingly in May to repeal its own strict laws.

When Ireland replaces the constitutional ban with more liberal legislation after a debate in parliament, Northern Ireland will be the only remaining region in Britain and Ireland to outlaw the procedure.

Rosa Curling, from the law firm Leigh Day that helped bring the legal challenge, called the court's ruling "a momentous day for women in Northern Ireland" and said it is now up to British Prime Minister Theresa May to take action to ease the laws.

She said May has an obligation to make sure the U.K. government is "now longer acting unlawfully by breaching the human rights of women across Northern Ireland."

However, the fact that the Supreme Court dismissed the case because of doubts about the Human Rights Commission's right to bring it means the judges' views on the anti-abortion laws do not have legal force, which is reassuring for abortion foes.